The instant application relates generally to the immunological techniques applied to native semen, and more specifically to a method for lowering the risk of the susceptibility to certain human diseases related to the human leukocyte antigen which is surface-affixed to human spermatozoa.
A large body of scientific data indicates that the risk of developing many chronic diseases is associated with specific antigens of the human leukocyte antigen (HLA) complex. Since the HLA antigens are surface-affixed to human spermatozoa in specific regions, it is possible with the method revealed hereinafter to expose an HLA antibody to spermatozoa in a semen sample and, after binding of the antibody to the HLA antigen, thereafter separate and eliminate the spermatozoa bearing a specific disease-associated HLA antigen from the remaining population. Spermatozoa lacking the disease-associated HLA antigen can thereinafter be used in artificial insemination to produce human offspring in which the possibility of the occurrence of an HLA associated disease has been greatly reduced. This process may be used when an analysis of the medical history of a prospective father or his family reveals a disease process associated with an HLA antigen expressed by the prospective father.
The prior art of which applicant is aware that may be germane to the patent process is as follows:
U.S. Pat. No. 4,191,749, Bryant;
U.S. Pat. No. 4,265,873, Sheehy et al;
U.S. Pat. No. 4,318,886, Kawahara et al;
Schaller, HOSP.
Dausett NATURE 225:191, 1970
Festenstein, Chapter 2 in Spermatozoa, Antibodies, and Infertility, 1978
Of great interest are the discoveries by Dausett and Festenstein which indicate that HLA antigens are expressed on individual sperm in accordance with the chromosome which it receives during meiotic segregation of the chromosome pair encoding HLA genes. Thus, the presence of a certain HLA antigen on the surface of the sperm indicates the presence of a corresponding gene contained in the haploid genetic material within the nucleus of the sperm cell. Therefore, a specific HLA gene produces a correspondingly specific HLA antigen which appears on the outer surface of the spermatozoa allowing binding by a specific antibody to the antigen. The binding and eventual elimination of the undesired sperm can be accomplished by the process revealed in the instant application without negatively affecting the remaining population of sperm in any given semen sample.
The patents to Kawahara et al and Sheehy et al are of general interest in that they reveal methods for typing human leukocyte antigens. Once typed, the antigens can be more specifically identified and an antibody can be produced which is specifically directed to that antigen. However, the aforecited patents and the Schaller article provide only background information which would not appear to impinge on the patentability of applicant's invention.
The remaining citation, being applicant's own patent, reveals a method of isolating sperm cells according to antigens indicative of the sex of an offspring that would result from the fertilization of an egg by a specific sperm. Applicant revealed in his previous patent a method for attaching a male specific antibody to a neutral bead, stacking the beads in a column, and passing a population of spermatozoa therethrough so that male specific spermatozoa were bound to the immunoabsorbent column of beads and female specific spermatozoa were not. After elution of the column the female specific spermatozoa can be retrieved from the medium. Similarly, the male specific spermatozoa may be eluted from the columns by employing the principle of competitive inhibition of cellular binding or other means, after which the male specific spermatozoa are available for artificial insemination.
The technology revealed in the instant application is distinguished from applicant's own prior art in that the instant application is directed towards the prevention of certain chronic diseases of genetically based susceptibility in human offspring, whereas the prior art patent was directed towards the sex selection of mammalian offspring. Furthermore, there are significant differences between the antigens produced by the sex chromosomes and the human leukocyte antigens produced by other chromosomes. There is significant debate in the scientific community as to whether or not the human leukocyte antigens affixed to the surface of spermatozoa are a product of the haploid genetic material contained within the cell itself or a product of the precursor diploid cell. Therefore, it is neither anticipated nor obvious to apply the methods and apparatus revealed in applicant's previous patent to the human leukocyte antigens in order to isolate a specific population of spermatozoa containing undesirable genetic characteristics as is accomplished by applying the methods to be revealed hereinafter.